Preliminary effects of oral uridine on the ocular surface in dry eye patients

The validity and reliability of the Arabic version of the ocular surface disease index (OSDI) questionnaire in a sample of the Gazan population: a study from Palestine

PURPOSE

To develop an Arabic version of OSDI for the Gazan population.

METHODS

A cross-sectional observational study was conducted using a convenience sample technique. The translation procedure included five stages: forward translation, revision of translation, backward translation, refinement of translation, and a final test of the pre-final version. The final sets of questionnaires were constructed using an online JotForm platform. The online platform was chosen to automatically calculate the questionnaire's final overall score. Overall, 260 participants were instructed to fill out the English and the Arab-OSDI version twice to conduct the reliability of the translated version and repeatability evaluation.

RESULTS

The mean age of the participants was 33.45 ± 11.74 years old. Cronbach's alpha for all items was greater than 0.80, except for the "blurred vision" and "deteriorating vision" items (0.77 and 0.74, respectively). The mean overall score difference between the English-OSDI and Arab-OSDI was 0.86 based on the Bland-Altman chart. For repeatability, no significant difference in the overall scores between the two repeats of the Arab-OSDI (p = 0.632). The Arab-OSDI overall score (sessions 1 and 2) has a clinical difference (bias) of 0.21. Using the varimax rotation method, only three factors (ocular symptoms, vision-related function, and environmental triggers) had eigenvalues greater than one in the structure of the Arab-OSDI.

CONCLUSION

The Arab-OSDI is an appropriate, reliable, and repeatable tool for the determination of dry eye symptoms, ocular discomfort, and quality of life in the Gazan population. This version could remove the language barrier in answering OSDI items more easily.

Placebo administration for dry eye disease: a level I evidence based systematic review and meta-analysis

Background

The efficacy of various common treatment options for dry eye disease (DED) has been investigated against placebo. However, the potential beneficial effect of placebo in the management of DED is still unclear.

Aim

This meta-analysis investigated the impact of placebo administration in DED in Ocular Surface Disease Index (OSDI), Schirmer I test (SIT), tear breakup time (TBUT), corneal staining, and complications.

Method

This meta-analysis and systematic review was conducted according to the 2020 PRISMA guidelines. In March 2022, Pubmed, Web of Science, Google Scholar, and Embase were accessed. All the randomised clinical trials which investigated any active treatment against a placebo control group were considered. The following data were extracted at baseline and at last follow-up: Ocular Surface Disease Index (OSDI), tear breakup time test (TBUT), Schirmer I test (SIT), corneal staining.

Results

Data from 56 studies (12,205 patients) were retrieved. Placebo administration is not effective in improving TBUT (P = 0.3), OSDI (P = 0.2), SIT (P = 0.1) and corneal staining (P = 0.1) from baseline to last follow-up. Active treatment led to a higher TBUT and SIT compared to placebo administration (P < 0.0001). The active treatment resulted in a lower OSDI compared to placebo administration (P = 0.0005). Five studies reported data on the corneal staining. No difference was found between placebo administration and active treatment (P = 0.8).

Conclusion

Placebo administration does not impact symptoms of DED and can be successfully employed to evaluate the efficacy of active treatments.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11096-022-01439-y.

A Review of Dry Eye Questionnaires: Measuring Patient-Reported Outcomes and Health-Related Quality of Life

Dry eye disease (DED) is among the most common eye diseases and is becoming increasingly prevalent. Its symptoms cause a long-term decline in patients’ health-related quality of life (HRQL). Inconsistencies often occur between the clinical findings and the subjective symptoms of DED. Therefore, a holistic, balanced, and quantitative evaluation of the subjective symptoms and HRQL using patient-reported outcome questionnaires, in addition to clinical findings, is crucial for accurate DED assessment in patients. This paper reviewed the characteristics of current dry eye questionnaires, including their objectives, number of questions, inclusion of HRQL-related items, and whether they were properly evaluated for psychometric properties. Twenty-four questionnaires were identified; among them, the following six questionnaires that included items assessing HRQL and were properly evaluated for psychometric properties are recommended: the Ocular Surface Disease Index, Impact of Dry Eye in Everyday Life, Dry Eye-Related Quality-of-life Score, University of North Carolina Dry Eye Management Scale, Chinese version of Dry Eye-Related Quality of Life, and 25-Item National Eye Institute Visual Function Questionnaire. Dry eye questionnaires have different objectives and are available in different languages. Therefore, medical practitioners should confirm the characteristics of applicable questionnaires before selecting the most appropriate ones.

A randomized controlled trial of omega-3 fatty acids in dry eye syndrome

AIM

To evaluate the role of dietary supplementation of omega-3 fatty acids in dry eye syndrome.

METHODS

A prospective, interventional, placebo controlled, double blind randomized trial was done at two referral eye centers. Two hundred and sixty-four eyes of patients with dry eye were randomized to receive one capsule (500mg) two times a day containing 325mg EPA and 175mg DHA for 3 months (omega-3 group). The omega-3 group was compared to a group of patients (n=254) who received a placebo (placebo group). There were 4 patient visits (at baseline, 1 month, 2 months and 3 months). On each visit, recording of corrected distance visual acuity (CDVA), slit lamp examination and questionnaire based symptom evaluation and scoring was done. A symptomatic score of 0-6 was mild, 6.1-12 moderate and 12.1-18 severe dry eye. Response to intervention was monitored by routine tear function tests like Schirmer I test, tear film break-up time (TBUT), Rose Bengal staining and most notably, conjunctival impression cytology.

RESULTS

Sixty-five percent of patients in the omega-3 group and 33% of patients in placebo group had significant improvement in symptoms at 3 months (P=0.005). There was a significant change in both Schirmer's test value and TBUT values in the omega-3 group (P<0.001), both comparisons. However, there was a larger drift in TBUT values in omega-3 than the placebo group, in comparison to Schirmer's test values. The mean TBUT score was 2.54±2.34 in the omega-3 group and 0.13±0.16 in placebo group, respectively. The mean reduction in symptom score in omega-3 group was 2.02±0.96 as compared to 0.48±0.22 in placebo group (P<0.001). Despite a slight increase mean score, the Schirmer scores did not correlate well with symptomatic improvement.

CONCLUSION

Omega-3 fatty acids have a definite role for dry eye syndrome. The benefit seems to be more marked in conditions such as blepharitis and meibomian gland disease. The role of omega fatty acids in tear production and secretion needs further evaluation.

Pharmacokinetics of uridine following ocular, oral and intravenous administration in rabbits

The pyrimidine nucleoside uridine has recently been reported to have a protective effect on cultured human corneal epithelial cells, in an animal model of dry eye and in patients. In this study, we investigate the pharmacokinetic profile of uridine in rabbits, following topical ocular (8 mg/eye), oral (450 mg/kg) and intravenous (100 mg/kg) administration. Blood and urine samples were serially taken, and uridine was measured by high-performance liquid chromatography-tandem mass spectrometry. No symptoms were noted in the animals after uridine treatment. Uridine was not detected in either plasma or urine after topical ocular administration, indicating no systemic exposure to uridine with this treatment route. Following a single intravenous dose, the plasma concentration of uridine showed a bi-exponential decay, with a rapid decline over 10 min, followed by a slow decay with a terminal half-life of 0.36 ± 0.05 h. Clearance and volume of distribution were 1.8 ± 0.6 L/h/kg and 0.58 ± 0.32 L/kg, respectively. The area under the plasma concentration-time curves (AUC) was 59.7 ± 18.2 μg·hr/ml, and urinary excretion up to 12 hr was ~7.7% of the dose. Plasma uridine reached a peak of 25.8 ± 4.1 μg/ml at 2.3 ± 0.8 hr after oral administration. The AUC was 79.0 ± 13.9 μg·hr/ml, representing ~29.4% of absolute bioavailability. About 1% of the oral dose was excreted in the urine. These results should prove useful in the design of future clinical and nonclinical studies conducted with uridine.

Goblet cells of the normal human bulbar conjunctiva and their assessment by impression cytology sampling

Goblet cells of the conjunctiva are the main source of mucus for the ocular surface. The objectives of this review are to consider the goblet cells as assessed by various histological, cytological and electron microscopy methods, and to assess the consistency of published reports (over more than 25 years) of goblet cell density (GCD) from impression cytology specimens from nominally healthy human subjects. Reported GCD values have been notably variable, with a range from 24 to 2226 cells/mm² for average values. Data analysis suggests that a high density of goblet cells should be expected for the healthy human conjunctiva, with a tendency toward higher values in samples taken from normally covered locations (inferior and superior bulbar conjunctiva) of the open eye (at 973 +/- 789 cells/ mm²) than in samples taken from exposed (interpalpebral) locations (at 427 +/- 376 cells/mm²). No obvious change in GCD was found with respect to age, perhaps because the variability of the data did not allow detection of any age-related decline in GCD. Analyses of published data from 33 other sources indicated a trend for GCD to be lower than normal across a spectrum of ocular surface diseases.

Sampling area selection for the assessment of goblet cell density from conjunctival impression cytology specimens

PURPOSE

To assess the impact of using different sampling areas (fields of view) on the reliability of goblet cell density (GCD) estimates from conjunctival impression cytology (CIC) specimens from healthy individuals.

METHODS

The CIC specimens were collected from the exposed nasal bulbar conjunctiva of 5 adult subjects (average age, 23 years) onto Biopore (Millicell) membranes and stained with Giemsa. A region from each of the specimens that contained abundant goblet cells was examined by light microscopy using a ×40 magnification objective lens, ×20 and ×10 lenses, the images were enlarged, and the goblet cells were marked and counted. The GCD values per square millimeter were calculated and then the impact of counting between 10 to many and 10 to few goblet cells assessed.

RESULTS

The mean GCD estimates at ×400 magnification, ×200, and ×100 were 950 ± 226, 620 ± 154 and 471 ± 158 cells per square millimeter, respectively; these values were statistically different (P<0.05). The GCD estimates could change by as much as ±31.6%, ±12.2%, and ±4.2% for differences of ±10 cells counted per image.

CONCLUSIONS

As a result of variability in goblet cell distribution across CIC specimens, the estimates of GCD can be expected to be different according to the sampling area used for goblet cell counts. Furthermore, the use of a small sampling area (high power field of view) is likely to result in an unacceptably large uncertainty (variability) in the GCD estimates.

Appraisal of patient-reported outcome instruments available for randomized clinical trials in dry eye: revisiting the standards

Clinical signs in dry eye (DE) often underestimate the severity of the condition, correlating poorly with symptoms and the impact on patients' health-related quality of life (HRQL). Patient-reported outcome (PRO) questionnaires are therefore essential to accurately evaluate the health status of DE patients and the severity of their condition. A comprehensive evaluation of HRQL in addition to clinical signs and visual function is necessary to fully characterize the impact of DE on patients' health. Growing interest in PRO measures and their implementation in clinical trials has resulted in more formal guidance on the design and properties of these instruments. To be scientifically sound and accepted by regulatory authorities, an instrument's development process and its appropriateness for use in the target population, its psychometric properties and responsiveness must be described. To address the recent health authority guidance, this review discusses the design, development methodology, and performance of currently available PRO instruments for DE.